This invention relates generally to non-destructive inspection of components and, more particularly, to inspection of components which include TV-shaped openings.
Gas turbine engines operate under adverse conditions and are frequently inspected. Many components are manufactured with integral TV-shaped openings which induce additional stresses on the components. Therefore, the components that include the openings are frequently inspected.
Fluorescent penetrant inspection (FPI) systems typically only detect cracks that are open to the surface of the component being inspected. However, in most components which include TV-shaped openings, the components are manufactured such that any pre-manufactured openings are in compression across the component. Because the component surfaces are in compression, any stresses induced within the components are directed from the surface inward, and therefore, the cracks may not be open to the surface. Therefore the FPI systems are ineffective for use with the TV-shaped openings.
Eddy current inspection methods detect cracks that are not open to the surface by inducing eddy currents within the material under inspection. Known eddy current methods for inspecting TV-shaped openings use eddy current machines which are expensive and bulky. In addition, the eddy current machines are large, impracticable to move, and often require a large area to operate. The gas turbine engine components must be brought to the location of the eddy current machine for inspection.
In an exemplary embodiment, an inspection apparatus includes a component engagement apparatus, a detection apparatus, and a movement apparatus. A drawer is slidably attached to the component engagement apparatus and receives and aligns a component including a TV-shaped opening into position for an inspection. The detection apparatus is sized to receive an eddy current probe and is attached to the movement apparatus with an adjustable fixture. The movement apparatus includes an indicator which identifies a position of the eddy current probe in relation to the TV-shaped opening being inspected, a cam assembly which guides movement of the movement apparatus, and a roller bearing assembly which facilitates movement of the movement apparatus.
In operation, the movement apparatus follows a cam profile which controls movement of the detection apparatus. The eddy current probe scans a portion of the TV-shaped opening and transmits data to an eddy scope. The inspection scans are then reliably repeated circumferentially around the TV-shaped opening. The inspection apparatus is easily transported from one location to another. As a result, the inspection apparatus eliminates more costly and more complicated known inspection equipment and provides a system that is accurate, portable, and cost-effective.